Table 1. Steady-state kinetic parameters for the methylation reaction catalyzed by PRC2WT, PRC2Y111L, PRC2Y641N and PRC2Y641N/Y661D.
| Proteins | H3 peptide | Km, SAM (x10-6M) | Km, H3 (21-44) (x10-6M) | kcat (x10-2/s) | kcat/Km, H3 (21-44) (x104/M/s) |
|---|---|---|---|---|---|
| WT | 21–44, Me0 | 1.1±0.1 | 0.7±0.08 | 1.6±0.05 | 2.4±0.1 |
| 21–44 [K27-CH3], Me1 | 1.3±0.2 | 0.9±0.1 | 1.7±0.06 | 1.9±0.1 | |
| 21–44 [K27-CH3]2, Me2 | − | − | − | − | |
| Y111L | 21–44, Me0 | 0.9±0.1 | 0.9±0.1 | 1.6±0.05 | 1.8±0.1 |
| 21–44 [K27-CH3], Me1 | 1.5±0.2 | 1.4±0.2 | 1.9±0.1 | 1.4±0.1 | |
| 21–44 [K27-CH3]2, Me2 | − | − | − | − | |
| Y641N | 21–44, Me0 | − | − | − | − |
| 21–44 [K27-CH3], Me1 | 0.9±0.1 | 0.7±0.09 | 0.6±0.02 | 0.9±0.1 | |
| 21–44 [K27-CH3]2, Me2 | 1.2±0.1 | 1.1±0.10 | 2.4±0.06 | 2.2±0.09 | |
| Y641N/Y661D | 21–44, Me0 | − | − | − | − |
| 21–44 [K27-CH3], Me1 | 4.6±1.0 | 2.8±0.6 | 0.9±0.07 | 0.3±0.2 | |
| 21–44 [K27-CH3]2, Me2 | 4.5±0.3 | 2.9±0.2 | 4.4±0.1 | 1.5±0.06 |
Abbreviations: WT, wild type; ‘-‘, not determined.